I can't see any justification for replacing it.
I don't think he was suggesting replacing your headlight with a headtorch.
Despite having FIERY-BEAMS-O-DETH (Solidlights XB2) I've certainly had situations on bends where a headtorch has picked out things coming up before the light does. Turning to the right means the bike is pitched over a bit. For the headlight to be illuminating that bit of road brightly would mean it would be pointing right into the eyes of oncoming drivers if I was riding along the straight. Your headlight isn't always pointing where you want to be going.
Back to phil d's question, I have tried headtorchs and not got on with them. I didn't like the added weight to the head
Fair enough.
and had trouble keeping it well placed on my helmet. Part of the problem arose with continually taking it on and off (because of the above meaning that I didn't want it on the helmet during daylight).
As
the previous photo I attached mine to the helmet by weaving it through the vents. It stays there permanently, even during daylight. (I can't see a reason why I'd worry about it being on there during daylight. One looks odd enough on a bike dressed for Audaxing anyway.)
Then there was the above the peak/below the peak question. If it were above the peak then it'll be partially blocked for map reading, below means less effective for looking around at signposts and other stuff.
Ah, I ripped off the peak on my helmet almost straight away and use a cotton cycling cap instead. Helps keep the majority of the rain off my glasses (except Welsh horizontal rain) and has the added benefit of taking the sweat off my head and making it drip off the tip of the peak.
I've never had a problem with the cap peak obscuring the beam, even when not wearing a helmet and wearing a headtorch (I have one for when I leave the helmet at home) on my head (on the cap).
To be fair I don't really need it for looking at signposts and other landmarks as, luckily, I've been blessed with good night vision, except when I've got a headtorch right above my eyes. Any rare instances of needing to shine a light on something are met by taking the handlebar light off and waving it around.
A headtorch is useful for info controls, mainly because there's less faffage. I've noticed this when I've forgotten it and had to use something else. A headtorch really comes in to its own when you need to do roadside repairs. It's a lot easier to do this with both hands free rather than having to hold a light or wedge it between neck and shoulder.
I have, on a couple of occasions even managed to out navigate GPS, it almost seems like downgrading.
Which is why I dislike auto-routing GPSes or following tracks. I use an old non-mapping GPS that simply gives me a representation of the routesheet. It counts down distance to the next routepoint I've programmed in with the routesheet instruction. It won't ever try and do something clever, and never gets a chance to think for itself. It simply tells me what I've told it to tell me at the preprogrammed points.
It's no magic box though, like a routesheet, it won't stop you missing your turn if you're not looking out for it, but at least it will tell you that the turn is now behind you when you next look at it (unlike a routesheet).